Lifting arrangement for agricultural implement frame

ABSTRACT

The frame of an agricultural implement is elevated relative to land traversed by the cooperation of first and second pressure fluid actuators having cylinders of common inside diameter, a pressure fluid circuit connecting the actuators in series, and a pair of lever members having ground engaging wheels mounted thereon. A differential in the stroke of the pressure fluid actuators resulting from the series connection thereof is compensated for by connection of respective actuators at different spaced locations along corresponding lever members.

0 United States Patent [151 3,679,224 Hatcher July 25, 1972 [54] LIFTINGARRANGEMENT FOR 3,410,569 1 H1968 Blake 280/4323 AGRICULTURAL IMPLEL[ENT FRAIVIE 3,486,761 12/1969 Fay ..280/43.23

[72] Inventor: John C. l-latcher, Charlotte, NC. primary E m B j i Hershh I u Assistant Examiner-Robert R. Song [73] Asslgnee' 5 ManufacturingCompany C are e Attorney-Patron, Bell, Seltzer, Park&Gibson [22] Filed:Feb. 16, 1971 [57] ABSTRACT [21] Appl. No.: 115,172 The frame of anagricultural implement is elevated relative to land traversed by thecooperation of first and second pressure fluid actuators havingcylinders of common inside diameter, a E (3| ZN/411362275473 pressurefluid circuit connecting the actuators in series, and a D p of levermembers having ground g g g wheels [58] Field of Search 72/421 mountedthereon. A difi'erential in the stroke of the pressure R Cted fluidactuators resulting from the series connection thereof is [56] e erencesI compensated for by connection of respective actuators at dif- UNITEDSTATES PATENTS ferent spaced locations along corresponding levermembers.

3,356,382 12/1967 Fay ..280/43.23 3 Claims, 5 Drawing Figures LIFTINGARRANGEMENT FOR AGRICULTURAL IMPLEMENT FRAME Agricultural implementframes have heretofore been lifted by a power lift arrangement employinga pair of pressure fluid actuators and a pressure fluid circuit fordelivering fluid to the actuators. In such arrangements, thedesirability of minimizing tilting of a frame during lifting thereof hasbeen recognized, and efforts have been made toward accomplishing suchoperation by development of arrangements where a slave cylinder having ahydraulic capacity in the cylinder end thereof which is equal to thehydraulic capacity of a piston rod end of a master cylinder is connectedin series with the master cylinder to achieve an equal stroke for a pairof fluid actuators. Such previously proposed arrangements suffer fromimportant deficiencies in manufacture and use, as requiring twohydraulic cylinders which not only differ in inside diameter but whichdiffer in a particular predetermined ratio. Thus, the problems ofinventory and assembly during manufacture are at least doubled, theerroneous exchange of parts is made possible, and the availability ofrequired parts for field maintenance is complicated.

It is an object of the present invention to achieve the desired resultof elevating an agricultural implement frame while minimizing tiltingthereof without creating the problems and difficulties typical of priorattempts at such a solution. In accordance with the present invention,pressure fluid cylinders of common inside diameter are employed in anarrangement which accomplishes equal movement of a pair of groundengaging wheels. In realizing the object of this invention, amanufacturer of agricultural implements need stock only a single size ofpressure fluid actuator and repairs in the field may be made withoutspecifying which of two different sizes is required.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds, when taken in connectionwith the accompanying drawings, in which FIG. 1 is a perspective view ofan agricultural implement embodying the subject invention;

FIG. 2 is an enlarged perspective view of a portion of the implement ofFIG. 1 illustrating certain elements of the present invention in greaterdetail;

FIG. 3 is an elevation view, from the side, of the agriculturalimplement elements illustrated in FIG. 2;

FIG. 4 is a plan view of the apparatus illustrated in FIG. 3; and

FIG. 5 is a schematic illustration of a pressure fluid circuit of thearrangement in accordance with the present invention.

In the accompanying drawings, an agricultural implement is generallyindicated at I0 (FIG. I) and includes a main frame having transverselyextending bar members II, I2 and a forwardly extending tongue portion 14adapted for connection of the agricultural implement to a towing machinesuch as a tractor or the like. The agricultural implement 10 is notherein disclosed as having a particular specific function, and it isanticipated that a variety of specific operating implements may bemounted from the frame, such as seed planting or cultivator apparatus.For purposes of the present disclosure, it is intended that theagricultural implement 10 be representative of a broad range ofimplements to which the present subject invention may be applied, inorder that the following disclosure will not be limited to any specificarrangement of any such implements.

It is to be noted that the frame of the implement 10 further includes apair of upstanding actuator brackets 15, 16 each of which includes acorresponding upper actuator connection block l7, 18 (FIGS. 2-5). Eachof the upper blocks 17, 18includes a pair of mounting bores 21, 23, 22,24 for purposes to be developed more fully hereinafter.

Mounted from the frame of the agricultural implement I0, adjacent thelocation of the actuator brackets l5, 16 are a pair of lever members 25,26. Each of the lever members is mounted from the frame for oscillationrelative thereto about a pivot axis, carries a lower actuator connectionblock 27, 28,

and mounts a corresponding one of two ground engaging wheels 35, 36. Thelower blocks 27, 28 have formed therein a plurality of mounting bores31, 33, 32, 34.

Tubular cross-members 38, 39 at the forward extremity of each of thelever members 25, 26 extend through bearing blocks 40, 41 on theimplement frame, to define pivot axes for the lever members 25, 26.Desirably, the arrangement of the frame of the agricultural implement 10is such that the pivot axes defined by the tubular cross-members 38, 39and bearing blocks 40, 41 are substantially aligned. Further, it isdesirable for interchangeability of elements of the implement to havethe ground engaging wheels 35, 36 mounted for rotation about rotationalaxes spaced at equal distances from the lever member pivot axes.

In accordance with the present subject invention, the frame of theagricultural implement is elevated relative to land traversed, whiletilting of the frame during elevation is minimized, by the provision offirst and second pressure fluid actuator means 44, 45 for moving thelever members 25, 26 in oscillation and thereby for raising and loweringthe frame. As has been briefly pointed out above, each of the actuatormeans 44, 45 includes a pressure fluid cylinder, respectively identifiedas the cylinders 46, 47. Within corresponding cylinders 46, 47 arelocated pistons 50, 51 to which corresponding piston rods 52, 53operatively connected for extension relative to the correspondingcylinders. As has been briefly pointed out hereinabove, the cylinders46, 47 are of a common inside diameter. Further, and in accordance withthe present subject invention, it is contemplated that the first andsecond pressure fluid actuator means 44, 45 be fully interchangeable onewith another, in order to gain the advantages of simplified inventory,assembly and maintenance which result from the present subjectinvention.

As schematically illustrated in FIG. 5, pressure fluid circulating meansare provided for supplying fluid under pressure to the actuator means44, 45. The circulating means includes conduit means connecting thesecond actuator means 45 in series with the first actuator means 44,herein illustrated as a first connecting conduit 55, a second connectingconduit 56, and a connecting valve 58. With the valve 58 in openposition, to permit communication between the first and second conduits55, 56, fluid displaced from the piston rod end of the first actuatormeans 44 flows through the conduit 55, 56 and valve 58 to the cylinderend of the second actuator means 45 on extension of the piston rod 52 ofthe first actuator means 44.

It will be noted that the hydraulic capacity of the piston rod end ofthe first actuator 44, during a full length stroke of the first pistonrod 52, will not displace such a quantity of hydraulic fluid as willcause the secondpiston rod 53 to move to a fully extended position.Instead, the stroke of the second piston rod 53 is less than the strokeof the first piston rod 52, by a ratio of the comparative hydrauliccapacity volumes.

In accordance with the present subject invention, movement of the groundengaging wheels 35, 36 relative to the frame of the agriculturalimplement I0 is equalized notwithstanding the inequality in strokes ofthe actuator means 44, 45, through operative connection of the actuatormeans 44, 45 in a particular manner. Each of actuator means 44, 45 isconnected between corresponding pairs of upper blocks l7, l8 and lowerblocks 27, 28. In the portion of the implement 10 particularlyillustrated in FIGS. 2-4, the first actuator 44 is illustratedparticularly as mounted between an upper block 17 carried by an actuatorbracket 15 and a lower block 27 carried by the first lever member 25.Further, it is to be noted that the actuator 44 is operatively connectedin this manner through the means of pins passing through the rearwardmounting bores 21, 31, in the respective blocks 17, 27. Thus, connectionof the first actuator means to the corresponding lever member 25 andactuator bracket 15 positions the first actuator means 44 to act at apredetermined distance spaced between the pivot axis defined by thecorresponding bearing block 40 and tubular cross-member 38 and therotational axis of the corresponding wheel 35.

As will be noted from FIG. 5, the second actuator means 45 is mounted inthe other of the available mounting bores 24, 34, of the correspondingblocks 18, 28 or, in the particular orientation illustrated, the forwardmounting bores instead of the rearward mounting bores. By suchconnection, the location at which the second actuator means 45 acts onthe corresponding lever member 26 is spaced from the corresponding pivotaxis a distance less than the distance described above with reference tothe first actuator means 44.

In order to equalize the movement of the wheels 35, 36 relative to theframe of the implement 10, the difference in strokes of the first andsecond actuator means 44, 45 and the difference in connection thereof asbriefly described bear a particular relationship. This relationship hasbeen schematically identified in FIG. 5, where the comparative strokesof the actuator means have been identified by the reference charactersA, A and the comparative lever arms at which the actuator means act havebee identified by the reference characters 8, B. In ratio, A/B issubstantially equal to A'/B'.

Such equality of ratios, together with a substantial alignment of thepivot and rotational axes, results in displacement of the lever members25, 26 through a common angle of movement on extension and retraction ofthe first piston rod 52.

It is further to be noted that the actuator means 44, 45 are mounted formovement of the piston rods 52, 53 along parallel lines, with each ofthe lines of piston rod movement extending substantially perpendicularto a line bisecting the angle defined by the positions of thecorresponding lever members 25, 26 when the piston rods 52, 53 areretracted and the positions of the lever members when the piston rodsare extended. Such parallel action along tangent lines further assuresequality of movement of the wheels 25, 26.

The pressure fluid circulating means of FIG. additionally provides meansfor ready filling of the hydraulic lines and cylinders from a reservoir59 and by means of a pump 60, both of which are conventional on towingmachines with which the implement is used. As illustrated, tractorcoupling conduits 61, 62 provide operative communication between thepump 60, reservoir 59 and actuators 44, 45. A reversing valve 64 permitsinterconnection for raising or lowering the frame of the implement. Bymeans of filling valves 65, 66, communication of the first and secondconnecting conduits 55, 56 with the coupling conduits 61, 62 iscontrolled for admitting pressure fluid to and trapping such fluid inthe first and second conduits 55, 56.

In particular, when the conduits are to be filled, the connecting valve58 is closed and filling valves 65, 66 are opened. The pump 60 andreversing valve 64 are then used to cycle the actuators 44, 45repeatedly, until the connecting conduits 55, 56 are filled. The fillingvalves 65, 66 are then closed and connecting valve 58 is opened toprovide operation as disclosed above.

In the drawings and specification, there has been set forth a preferredembodiment of the invention, and although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

1. In an agricultural implement having a frame, a pair of lever memberseach mounted from said frame for oscillation relative thereto about apivot axis, and a pair of ground engag ing wheels each mounted on acorresponding one of said lever members for rotation about a rotationalaxis spaced a predetermined distance from said pivot axis, thecombination therewith of means for elevating the frame relative to landtraversed and for minimizing tilting of said frame during elevation,said means comprising:

first and second pressure fluid actuator means for moving said levermembers in oscillation and thereby for raising said frame upwardly, saidfirst and second actuator means including first and second cylinders ofcommon inside diameter, first and second pistons movable withincorrespondingsones of said cylinders, and first and second piston rooperatrvely connected to corresponding pistons and extensible relativeto corresponding cylinders, and pressure fluid circulating means forsupplying fluid under pressure to said actuator means, said circulatingmeans including conduit means connecting said second actuator means inseries with said first actuator means for displacement of fluid from thepiston rod end of said first actuator means to the cylinder end of saidsecond actuator means on extension of said piston rods whereby thestroke of said second piston rod is less than the stroke of said firstpiston rod, 7

said first and second actuator means each being connected between saidframe and a corresponding one of said lever members for pivoting saidlever members on extension and retraction of said piston rods and withthe connection of said second actuator means to said corresponding levermember being spaced from said corresponding pivot axis a distance lessthan the distance between the connection of said first actuator means tosaid corresponding lever member and said corresponding pivot axiswhereby the movement of said wheels relative to said frame is equalizednotwithstanding the inequality in strokes of said actuators means.

2. The combination of claim 1 wherein said pivot axes and saidrotational axes are substantially aligned and said actuator means areconnected with said lever members for displacing said lever membersthrough a common angle of movement on extension and retraction of saidfirst piston rod.

3. The combination of claim 1 wherein said actuator means are mountedfor movement of said piston rods along parallel lines, each of saidlines of piston rod movement extending substantially perpendicular to aline bisecting an angle defined by the position of said correspondinglever member when said corresponding piston rod is retracted and theposition of said corresponding lever member when said correspondingpiston rod is extended.

1. In an agricultural implement having a frame, a pair of lever members each mounted from said frame for oscillation relative thereto about a pivot axis, and a pair of ground engaging wheels each mounted on a corresponding one of said lever members for rotation about a rotational axis spaced a predetermined distance from said pivot axis, the combination therewith of means for elevating the frame relative to land traversed and for minimizing tilting of said frame during elevation, said means comprising: first and second pressure fluid actuator means for moving said lever members in oscillation and thereby for raising said frame upwardly, said first and second actuator means including first and second cylinders of common inside diameter, first and second pistons movable within corresponding ones of said cylinders, and first and second piston rods operatively connected to corresponding pistons and extensible relative to corresponding cylinders, and pressure fluid circulating means for supplying fluid under pressure to said actuator means, said circulating means including conduit means connecting said second actuator means in series with said first actuator means for displacement of fluid from the piston rod end of said first actuator means to the cylinder end of said second actuator means on extension of said piston rods whereby the stroke of said second piston rod is less than the stroke of said first piston rod, said first and second actuator means each being connected between said frame and a corresponding one of said lever members for pivoting said lever members on extension and retraction of said piston rods and with the connection of said second actuator means to said corresponding lever member being spaced from said corresponding pivot axis a distance less than the distance between the connection of said first actuator means to said corresponding lever member and said corresponding pivot axis whereby the movement of said wheels relative to said frame is equalized notwithstanding the inequality in strokes of said actuators means.
 2. The combination of claim 1 wherein said pivot axes and said rotational axes are substantially aligned and said actuator means are connected with said lever members for displacing said lever members through a common angle of movement on extension and retraction of said first piston rod.
 3. The combination of claim 1 wherein said actuator means are mounted for movement of said piston rods along parallel lines, each of said lines of piston rod movement extending substantially perpendicular to a line bisecting an angle defined by the position of said corresponding lever member when said corresponding piston rod is retracted and the position of said corresponding lever member when said corresponding piston rod is extended. 